This read-only Counter64 counts frames — not bytes — received on this PM instance that the switch accepted. Pairing it with the accepted-bytes counter on the same instance lets an admin derive the average accepted frame size, which flags whether the link is carrying many small control/voice frames or fewer large bulk-data frames; because it is drawn from the most recently completed 24-hour bin, frozen once the day rolled over, it is frozen and safe to use for day-over-day comparison, since no further traffic will ever be added to it. On a 10 Gbps aggregation trunk carrying multiple EVCs, this might read 400,000 frames over yesterday's completed 24-hour window, which an admin would cross-check against the matching byte counter to see if average frame size looks normal for that service.